1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* -*- linux-c -*- ------------------------------------------------------- *
3 *
4 * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
5 *
6 * ----------------------------------------------------------------------- */
7
8 /*
9 * mktables.c
10 *
11 * Make RAID-6 tables. This is a host user space program to be run at
12 * compile time.
13 */
14
15 #include <stdio.h>
16 #include <string.h>
17 #include <inttypes.h>
18 #include <stdlib.h>
19 #include <time.h>
20
21 static uint8_t gfmul(uint8_t a, uint8_t b)
22 {
23 uint8_t v = 0;
24
25 while (b) {
26 if (b & 1)
27 v ^= a;
28 a = (a << 1) ^ (a & 0x80 ? 0x1d : 0);
29 b >>= 1;
30 }
31
32 return v;
33 }
34
35 static uint8_t gfpow(uint8_t a, int b)
36 {
37 uint8_t v = 1;
38
39 b %= 255;
40 if (b < 0)
41 b += 255;
42
43 while (b) {
44 if (b & 1)
45 v = gfmul(v, a);
46 a = gfmul(a, a);
47 b >>= 1;
48 }
49
50 return v;
51 }
52
53 int main(int argc, char *argv[])
54 {
55 int i, j, k;
56 uint8_t v;
57 uint8_t exptbl[256], invtbl[256];
58
59 printf("#ifdef __KERNEL__\n");
60 printf("#include <linux/export.h>\n");
61 printf("#endif\n");
62 printf("#include <linux/raid/pq.h>\n");
63
64 /* Compute multiplication table */
65 printf("\nconst u8 __attribute__((aligned(256)))\n"
66 "raid6_gfmul[256][256] =\n"
67 "{\n");
68 for (i = 0; i < 256; i++) {
69 printf("\t{\n");
70 for (j = 0; j < 256; j += 8) {
71 printf("\t\t");
72 for (k = 0; k < 8; k++)
73 printf("0x%02x,%c", gfmul(i, j + k),
74 (k == 7) ? '\n' : ' ');
75 }
76 printf("\t},\n");
77 }
78 printf("};\n");
79 printf("#ifdef __KERNEL__\n");
80 printf("EXPORT_SYMBOL(raid6_gfmul);\n");
81 printf("#endif\n");
82
83 /* Compute vector multiplication table */
84 printf("\nconst u8 __attribute__((aligned(256)))\n"
85 "raid6_vgfmul[256][32] =\n"
86 "{\n");
87 for (i = 0; i < 256; i++) {
88 printf("\t{\n");
89 for (j = 0; j < 16; j += 8) {
90 printf("\t\t");
91 for (k = 0; k < 8; k++)
92 printf("0x%02x,%c", gfmul(i, j + k),
93 (k == 7) ? '\n' : ' ');
94 }
95 for (j = 0; j < 16; j += 8) {
96 printf("\t\t");
97 for (k = 0; k < 8; k++)
98 printf("0x%02x,%c", gfmul(i, (j + k) << 4),
99 (k == 7) ? '\n' : ' ');
100 }
101 printf("\t},\n");
102 }
103 printf("};\n");
104 printf("#ifdef __KERNEL__\n");
105 printf("EXPORT_SYMBOL(raid6_vgfmul);\n");
106 printf("#endif\n");
107
108 /* Compute power-of-2 table (exponent) */
109 v = 1;
110 printf("\nconst u8 __attribute__((aligned(256)))\n"
111 "raid6_gfexp[256] =\n" "{\n");
112 for (i = 0; i < 256; i += 8) {
113 printf("\t");
114 for (j = 0; j < 8; j++) {
115 exptbl[i + j] = v;
116 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
117 v = gfmul(v, 2);
118 if (v == 1)
119 v = 0; /* For entry 255, not a real entry */
120 }
121 }
122 printf("};\n");
123 printf("#ifdef __KERNEL__\n");
124 printf("EXPORT_SYMBOL(raid6_gfexp);\n");
125 printf("#endif\n");
126
127 /* Compute log-of-2 table */
128 printf("\nconst u8 __attribute__((aligned(256)))\n"
129 "raid6_gflog[256] =\n" "{\n");
130 for (i = 0; i < 256; i += 8) {
131 printf("\t");
132 for (j = 0; j < 8; j++) {
133 v = 255;
134 for (k = 0; k < 256; k++)
135 if (exptbl[k] == (i + j)) {
136 v = k;
137 break;
138 }
139 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
140 }
141 }
142 printf("};\n");
143 printf("#ifdef __KERNEL__\n");
144 printf("EXPORT_SYMBOL(raid6_gflog);\n");
145 printf("#endif\n");
146
147 /* Compute inverse table x^-1 == x^254 */
148 printf("\nconst u8 __attribute__((aligned(256)))\n"
149 "raid6_gfinv[256] =\n" "{\n");
150 for (i = 0; i < 256; i += 8) {
151 printf("\t");
152 for (j = 0; j < 8; j++) {
153 invtbl[i + j] = v = gfpow(i + j, 254);
154 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
155 }
156 }
157 printf("};\n");
158 printf("#ifdef __KERNEL__\n");
159 printf("EXPORT_SYMBOL(raid6_gfinv);\n");
160 printf("#endif\n");
161
162 /* Compute inv(2^x + 1) (exponent-xor-inverse) table */
163 printf("\nconst u8 __attribute__((aligned(256)))\n"
164 "raid6_gfexi[256] =\n" "{\n");
165 for (i = 0; i < 256; i += 8) {
166 printf("\t");
167 for (j = 0; j < 8; j++)
168 printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1],
169 (j == 7) ? '\n' : ' ');
170 }
171 printf("};\n");
172 printf("#ifdef __KERNEL__\n");
173 printf("EXPORT_SYMBOL(raid6_gfexi);\n");
174 printf("#endif\n");
175
176 return 0;
177 }
178
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